..The physical chromosome segregation defects seen in rad12 null cells combined with the checkpoint regulation defect seen in the rad12+ overproducer implicate rad12+ as a key coupler of chromosomal integrity with cell cycle progression...

The human G2 checkpoint control protein hRAD9 is a nuclear phosphoprotein that forms complexes with hRAD1 and hHUS1

..Finally, we show that hRAD9 is a nuclear protein, indicating that in this signal transduction pathway, hRAD9 is physically proximal to the upstream (DNA damage) signal rather than to the downstream, cytoplasmic, cell cycle machinery...

DNA damage-dependent and -independent phosphorylation of the hRad9 checkpoint protein